Numerous mechanisms have been designed and built for converting the energy of moving fluid, such as air or water, to mechanical energy. Commonly known mechanisms for converting the energy of moving water to mechanical energy are water wheels, paddles and turbines. Generally speaking, mechanisms for converting the energy of a moving fluid to mechanical power have tended throughout their evolution to become both more complicated and more costly to manufacture. Modern axial flow turbine systems typically require the construction of dams or diversions and penstocks to support even low-head power production. The present invention was developed in an effort to provide a low cost in-stream system for utilizing the energy in a fluid stream, particularly a small slow moving stream, as a pumping station or a small scale electrical generator such as might be used effectively in remote or undeveloped areas around the world.
In the early 1900s, John Roeh patented an Automatic Current Motor, U.S. Pat. Nos. 705,967 and 804,676, that extracted energy from a stream flow using a vane attached to a tiller. As the water flows past the vane, the vane automatically sweeps back and forth across the stream under the bi-directional control of a cross cabling system. A connecting rod transmits the energy in the oscillating tiller to some type of receiving machine to produce useful work. Mr. Roeh's system, while presenting a potentially workable small scale in-stream generating or pumping station, is disadvantageous because it requires a fairly complex mechanical linkage to achieve the bi-directional control necessary to make the vane sweep automatically back and forth across the stream.